The present invention relates generally to electron sources, and more particularly to focusing and steering electrons from the electron sources, such as field emitters.
An easy-to-build flat panel display has been considered as the "Holy Grail" in electronics. Numerous researchers have been trying to invent such a display. One of the hurdles of the display is to easily and inexpensively focus and steer the electrons emitted from the electron sources to the screen of the display.
Various devices have been used to focus and steer the emitted electrons. One method depends on layers of metallic grides hanging directly above the sources. Displays with these grids are expensive and difficult to make reliably.
Another method, known as the "switched anode" method, depends on positioning the screen of the display very close to the electron sources and then dynamically varying voltages on the screen to attract and to guide the electrons. To prevent voltage breakdown between the screen and the electron sources, the voltage difference between the screen and the sources should be low. With a significant portion of the electrons attracted to the gates controlling the sources and missing the screen, the power efficiency of the display is low. Also, the voltage on the screen typically limits the brightness of the display, and the potential difference between adjacent stripes on the screen limit the resolution of the display.
It should be apparent from the foregoing that there is still a need for apparatus and methods to efficiently focus and steer electrons in a flat panel display.